Volume 36, Issue 1, March 2007
Index of content:
Permittivity of Pure Water, at Standard Atmospheric Pressure, over the Frequency Range and the Temperature Range36(2007); http://dx.doi.org/10.1063/1.2360986View Description Hide Description
All the currently available experimental permittivity data for pure water are used to derive an interpolation function that precisely represents at standard atmospheric pressure, for frequencies and temperatures in the ranges and . The permittivity data is represented in terms of relaxations and resonances processes. There are three relaxations in the microwave region and two resonances in the far infrared. The temperature dependence of the relaxation and resonance parameters are determined. For example, at the three relaxation frequencies are , , and the two resonance frequencies are 4.03 and .
Prediction of Enthalpy of Formation in the Solid State (at ) Using Second-Order Group Contributions—Part 2: Carbon-Hydrogen, Carbon-Hydrogen-Oxygen, and Carbon-Hydrogen-Nitrogen-Oxygen Compounds36(2007); http://dx.doi.org/10.1063/1.2435401View Description Hide Description
A program has been undertaken to develop a new group contribution method, based on Benson’s group additivity technique, estimate as precisely as possible solid state enthalpies of formation, at , of compounds,compounds, and compounds. A set of 1017 experimental values of the enthalpy of formation has been studied and compared to the predicted values of this new method as well as the method of Domalski and Hearing. This new estimation technique leads to a higher precision and reliability. With the inclusion of additional group values, a wider range of compounds can be studied (compared to the Domalski and Hearing technique). Comparison with a quantum mechanical method [Rice et al., Combust. Flame118, 445 (1999)] shows that the list of group contribution values, ring strain corrections, and non-nearest neighbor interactions provided here yields better estimates overall.
IUPAC-NIST Solubility Data Series. 82. Alcohols with Water—Revised and Updated: Part 1. Alcohols with Water36(2007); http://dx.doi.org/10.1063/1.2366707View Description Hide Description
The mutual solubility and related liquid–liquid equilibria of alcohols with water are exhaustively and critically reviewed. Reports of experimental determination of solubility in three chemically distinct binary systems that appeared in the primary literature prior to end of 2004 are compiled. For all the systems sufficient data are available to allow critical evaluation. All data are expressed as mass percent and mole fraction as well as the originally reported units. In addition to the standard evaluation criteria used throughout the Solubility Data Series, a new method based on the evaluation of all experimental data for a given homologous series of saturated alcohols was used.
IUPAC-NIST Solubility Data Series. 82: Alcohols with Water—Revised and Updated: Part 2. Alcohols with Water36(2007); http://dx.doi.org/10.1063/1.2366719View Description Hide Description
The mutual solubility and related liquid–liquid equilibria of alcohols with water are exhaustively and critically reviewed. Reports of experimental determination of solubility in ten chemically distinct binary systems for which data appeared in the primary literature prior to the end of 2004 are compiled. For eight systems sufficient data are available to allow critical evaluation. All data are expressed as mass percent and mole fraction as well as the originally reported units. In addition to the standard evaluation criteria used throughout the Solubility Data Series, a new method based on the simultaneous evaluation of the all experimental data, which includes liquid–liquid equilibrium correlation and prediction.
36(2007); http://dx.doi.org/10.1063/1.2432887View Description Hide Description
In this article, dynamic couplings for -, -, and -, by using first and second derivatives terms neglected in the Born–Oppenheimer approximation, are calculated. Newly calculated radiative transition probabilities for the and emission bands of are used to calculate the radiative and nonradiative lifetimes of the various vibrational levels and of and states of the diatomic potassium hydride, , molecule. For higher vibrational levels, an estimate of the bound-to-free emission probability is also needed and included. Accurate positions, radiative and nonradiative lifetimes of states belonging to the adiabatic and states of the molecule are estimated. The results come from a Fermi’s Golden Rule treatment in coupling calculation. That confirms the accuracy reached in both approaches and also in the treatment of the diabatic-adiabatic transformation. It involves, in particular, an effective phase choice that is needed to properly estimate nonadiabatic couplings.
QSPR Modeling of Partition Coefficients and Henry’s Law Constants for 75 Chloronaphthalene Congeners by Means of Six Chemometric Approaches—A Comparative Study36(2007); http://dx.doi.org/10.1063/1.2432888View Description Hide Description
-octanol/water and -octanol/air partition coefficients were calculated for 75 chloronaphthalenes (CNs) by means of quantitative structure-property relationship (QSPR) strategy to fill significant lacks in the empirical data. The QSPR models based on quantum-chemical descriptors computed on the level of density functional theory using B3LYP functional and 6- basis set. For each property, six models were identified using chemometric approaches such as: multiple regression method, principal component regression, partial least square regression, partial least square regression with initial elimination of the uninformative variables, partial least square regression with variable selection by a genetic algorithm (GA-PLS), and neural networks with variable selection by a genetic algorithm (GA-NN). They were calibrated and validated using the experimentally measured values of available for 16 congeners and the values of existing for 43 congeners. The models were compared regarding to their complexity and prediction ability. For best predictive model values of 75 CNs varied from 3.93 to 6.68, while that of , from 5.93 to 11.64. Root mean square errors of prediction for the best (GA-NN) models were 0.065 and 0.091, respectively. Further, values of and of CNs were calculated based on predicted and data. Depending on the CN congener varied from to and that of from 0.02 to 51.24. The errors of partitioning data computed in this study were of the same order of magnitude as reported for experimentally derived partitioning data, which confirmed applicability of the proposed modeling scheme for successful determination of and . Accordingly, a new procedure of the computational partitioning data generation based on partial least square regression with variable selection by a genetic algorithm (GA-PLS) and neural networks with variable selection by a genetic algorithm (GA-NN) was optimized and proposed for future use.
36(2007); http://dx.doi.org/10.1063/1.2227036View Description Hide Description
The energy levels and observed spectral lines of the krypton atom, in all stages of ionization for which experimental data are available, have been compiled. Sufficient data were found to generate level and line tables for Kr I–Kr X and Kr XVIII–Kr XXXVI. For Kr XXXV and Kr XXXVI and most of Kr XXXIV theoretical values are compiled for the energy levels. In all of the other stages a few lines, some of which may be only tentative classifications, are reported. In addition for Kr I, separate tables of energy levels are tabulated for the isotopes and . Experimental factors are included for Kr I and Kr II. A value, either experimental, semiempirical, or theoretical, is included for the ionizationenergy of each ion.